Field of the Disclosure
The present disclosure relates to a method for fabricating a circuit board structure, which can reduce the fabrication cost.
Description of the Related Art
A circuit board is mainly used to mechanically support and electrically connect electronic components, and thus is an essential component in electronic products.
FIG. 1A is a schematic top view of a conventional circuit board structure, in which the conventional circuit board may be a motherboard with a processor 10, a memory, 12, a power 14, I/O connectors 16, active and passive components, and conductive wires (not shown in FIG. 1A) disposed thereon. It should be realized that the electronic components such as the processor 10, the memory 12, and the power 14 and so on usually have complex circuit layouts, and therefore need to be supported by a multilayer circuit board (such as 8 layers, 10 layers, or more layers in the circuit board). However, a single circuit board only has a specific number of layers, thus resulting in the entire circuit board (comprising an area A where the processor 10, the memory 12, and the power 14 are located, and an area B, outside the area A, where the I/O connectors 16 and other active and passive components are located) should be fabricated by a multilayer (such as 8 layers, 10 layers, or more layers) process, such that the fabrication cost is increased.
To solve this problem, a known method utilizing a separated main board and small boards is used (FIG. 1B), wherein the electronic components like the processor 10, the memory 12, and the power 14 are mounted on a main board A fabricated by the multilayer process, and the I/O connectors 16 and other active and passive components are mounted on other small boards B1˜B3 having less than four layers. Also, the main board A and the small boards B1˜B3 are connected with each other by various cables. However, this method can reduce the fabrication cost of a large-area multilayer circuit board, but it also increases other additional costs, such as cables, cable connectors, and assembly costs. Moreover, the use of cables can easily cause some derivative problems, such as signal attenuation and electromagnetic interference (EMI).